Selecting Triple Negative Breast Cancer Patients for Immunotherapy

The KEYNOTE-522 study evaluated the addition of the anti-PD-1 monoclonal antibody pembrolizumab to chemotherapy for early-stage TNBC. Patients treated with preop-erative pembrolizumab experienced a significant improvement in pCR and an EFS benefit of 7 months, independent of PD-L1 status, leading to FDA approval in July 2021. Eligibility is mainly based on clinical stage, and surgeons and medical oncolo-gists should carefully evaluate T and N stages for optimal inclusion of T1cN1-2 and T2-4N0 patients. IrAEs present a challenge in the management of these patients, and physicians need to be aware of the presentation and timeline of these sometimes-severe complications, which can be permanent. Patient selection and out-comes will continue to improve as we better understand the ideal chemotherapy back-bone, the duration and necessity of adjuvant pembrolizumab, and biomarkers to better inform patient selection.